[away3d] [Broomstick] Drag3D & Orthographic unproject

[Driley]

 
I'm using the Drag3D class to get Intersects on a plane, which works 
perfectly when using a perspective lens.
 
But it seems to go a bit crazy when using an orthographic lens... Is this an 

issue/bug or am I being a Muppet?
 
 
Thanks
 
Dan